JP7390837B2 - Substrate processing method and substrate processing apparatus - Google Patents

Description

The present disclosure relates to a substrate processing method and a substrate processing apparatus.

2. Description of the Related Art The manufacturing process of a semiconductor device includes a liquid processing process in which liquid processing is performed by supplying a processing liquid to a substrate such as a semiconductor wafer. One such liquid treatment is a chemical cleaning process or a wet etching process, which is performed by supplying a heated chemical to the center of the surface of a rotating substrate. The temperature of the heated chemical solution supplied to the center of the substrate decreases before it spreads to the periphery of the substrate. Further, the substrate tends to cool down at the peripheral edge of the substrate where the circumferential speed is high. For this reason, heated liquid such as water is supplied to the back surface of the substrate to make the temperature of the substrate uniform (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2015-057816

The present disclosure provides a technique for increasing in-plane uniformity of liquid processing while suppressing consumption of processing liquid in liquid processing in which a chemical liquid is supplied to a rotating substrate.

A substrate processing method according to one aspect of the present disclosure includes a substrate temperature raising step of heating the substrate to increase the temperature of the substrate, and after the substrate temperature raising step, heating the substrate and rotating the substrate at a first rotation speed. a liquid film forming step of supplying a prewetting liquid to the first surface of the substrate while causing a prewetting liquid to form a liquid film of the prewetting liquid on the first surface of the substrate; a chemical solution treatment step of supplying a chemical solution to a first surface of the substrate while heating and rotating at a second rotation speed lower than the first rotation speed, and treating the first surface of the substrate with the chemical solution; The method further includes a substrate temperature lowering step of lowering the temperature of the substrate after the chemical treatment step.

According to the present disclosure, the in-plane uniformity of the liquid treatment can be improved in the liquid treatment in which a chemical liquid is supplied to a rotating substrate.

FIG. 1 is a longitudinal side view of a substrate processing system according to an embodiment of a substrate processing apparatus. 2 is a schematic longitudinal sectional view showing an example of the configuration of a processing unit provided in the substrate processing system of FIG. 1. FIG. It is a piping system etc. diagram which shows an example of the temperature control DIW supply mechanism which supplies temperature control DIW to the back nozzle of a processing unit. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. FIG. 3 is an action diagram illustrating a liquid treatment process according to an embodiment. 7 is a graph illustrating an example of a change in wafer temperature from a wafer temperature raising process to a rinsing process. 1 is a piping system diagram schematically showing an example of HDIW and CDIW piping systems in a substrate processing system. FIG. 7 is a piping system diagram schematically showing another example of the HDIW piping system in the substrate processing system.

One embodiment of a substrate processing apparatus will be described with reference to the accompanying drawings.

FIG. 1 is a diagram showing a schematic configuration of a substrate processing system according to this embodiment. In the following, in order to clarify the positional relationship, an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other are defined, and the positive direction of the Z-axis is defined as a vertically upward direction.

As shown in FIG. 1, the substrate processing system 1 includes a loading/unloading station 2 and a processing station 3. The loading/unloading station 2 and the processing station 3 are provided adjacent to each other.

The loading/unloading station 2 includes a carrier mounting section 11 and a transport section 12. A plurality of carriers C that horizontally accommodate a plurality of substrates, in this embodiment semiconductor wafers (hereinafter referred to as wafers W), are placed on the carrier mounting section 11 .

The transport section 12 is provided adjacent to the carrier mounting section 11 and includes a substrate transport device 13 and a delivery section 14 inside. The substrate transfer device 13 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 13 is capable of horizontal and vertical movement and rotation about a vertical axis, and uses a wafer holding mechanism to transfer the wafer W between the carrier C and the transfer section 14. conduct.

The processing station 3 is provided adjacent to the transport section 12 . The processing station 3 includes a transport section 15 and a plurality of processing units 16. The plurality of processing units 16 are arranged side by side on both sides of the transport section 15 .

The transport unit 15 includes a substrate transport device 17 therein. The substrate transfer device 17 includes a wafer holding mechanism that holds the wafer W. Further, the substrate transfer device 17 is capable of horizontal and vertical movement and rotation about a vertical axis, and is capable of transferring wafers W between the transfer section 14 and the processing unit 16 using a wafer holding mechanism. I do.

The processing unit 16 performs predetermined substrate processing on the wafer W transported by the substrate transport device 17 .

The substrate processing system 1 also includes a control device 4 . The control device 4 is, for example, a computer, and includes a control section 18 and a storage section 19. The storage unit 19 stores programs that control various processes executed in the substrate processing system 1. The control unit 18 controls the operation of the substrate processing system 1 by reading and executing a program stored in the storage unit 19 .

Note that this program may be one that has been recorded on a computer-readable storage medium, and may be installed in the storage unit 19 of the control device 4 from the storage medium. Examples of computer-readable storage media include hard disks (HD), flexible disks (FD), compact disks (CD), magnetic optical disks (MO), and memory cards.

In the substrate processing system 1 configured as described above, first, the substrate transfer device 13 of the loading/unloading station 2 takes out the wafer W from the carrier C placed on the carrier mounting section 11, and receives the taken out wafer W. Place it on Watabe 14. The wafer W placed on the transfer section 14 is taken out from the transfer section 14 by the substrate transfer device 17 of the processing station 3 and carried into the processing unit 16.

The wafer W carried into the processing unit 16 is processed by the processing unit 16, and then carried out from the processing unit 16 by the substrate transfer device 17 and placed on the transfer section 14. Then, the processed wafer W placed on the transfer section 14 is returned to the carrier C of the carrier mounting section 11 by the substrate transfer device 13.

Next, the configuration of the processing unit 16 will be explained with reference to FIG. 2.

The processing unit 16 includes a chamber 20, a substrate holding/rotating mechanism 30, a first processing fluid supply section 40, a second processing fluid supply section 50, and a recovery cup 60.

The chamber 20 accommodates the substrate holding rotation mechanism 30 and the collection cup 60. An FFU (Fan Filter Unit) 21 is provided on the ceiling of the chamber 20 . FFU 21 forms a downflow within chamber 20 .

The substrate holding/rotating mechanism 30 includes a substrate holding section 31 , a support section 32 , and a rotation driving section 33 . The substrate holder 31 is configured as a mechanical chuck having a disc-shaped base 31a and a plurality of gripping claws 31b provided at intervals in the circumferential direction on the outer peripheral edge of the base 31a. The substrate holding section 31 holds the wafer W horizontally using gripping claws 31b. When the gripping claws 31b grip the substrate, a gap is formed between the upper surface of the base 31a and the lower surface of the wafer W.

The support column 32 is a hollow member extending in the vertical direction. The upper end of the support column 32 is connected to the base 31a. When the rotation driving section 33 rotates the support column 32, the substrate holding section 31 and the wafer W held therein rotate around the vertical axis.

The collection cup 60 is arranged so as to surround the substrate holding section 31. The collection cup 60 collects processing liquid scattered from the rotating wafer W held by the substrate holder 31. A drain port 61 is formed at the bottom of the collection cup 60 . The processing liquid collected by the collection cup 60 is discharged to the outside of the processing unit 16 from the liquid drain port 61 . An exhaust port 62 is formed at the bottom of the collection cup 60. The internal space of the collection cup 60 is sucked through the exhaust port 62. The gas supplied from the FFU 21 is drawn into the recovery cup 60 and then exhausted to the outside of the processing unit 16 via the exhaust port 62.

The first processing fluid supply section 40 supplies various processing fluids (liquid, gas, gas-liquid mixed fluid, etc.) to the upper surface of the wafer W held by the substrate holding section 31 (usually the surface of the wafer W on which devices are formed). supply. The first processing fluid supply unit 40 includes a plurality of surface nozzles 41 that discharge processing fluid toward the upper surface (first surface) of the wafer W. The number of surface nozzles 41 is provided as many as necessary to perform the processing performed by the processing unit 16. Although five surface nozzles 41 are depicted in FIG. 2, the number is not limited to this.

The first processing fluid supply section 40 has one or more (two in the illustrated example) nozzle arms 42 . Each nozzle arm 42 carries at least one of the plurality of surface nozzles 41. Each nozzle arm 42 can move the surface nozzle 41 carried thereon between a position approximately directly above the center of rotation of the wafer W (processing position) and a retracted position outside the upper end opening of the collection cup 60. can.

Each of the surface nozzles 41 is supplied with processing fluid from a corresponding processing fluid supply mechanism 43 . The processing fluid supply mechanism 43 includes a processing fluid supply source such as a tank, cylinder, factory power, etc., a supply pipe line that supplies the processing fluid from the processing fluid supply source to the surface nozzle 41, and an on-off valve provided in the supply pipe line. and a flow control device such as a flow control valve. A drain line can be connected to the supply line in order to discharge the processing fluid (in particular, the processing liquid) remaining in the surface nozzle 41 and the supply line in the vicinity thereof. Such a processing fluid supply mechanism 43 is widely known in the technical field of semiconductor manufacturing equipment, and illustrations and detailed description of the structure will be omitted. The processing unit 16 is provided with a liquid receiver (not shown) so that dummy dispensing is possible when each surface nozzle 41 is in the retracted position.

The second processing fluid supply section 50 supplies various processing fluids (processing liquids, processing gases, etc.) to the lower surface of the wafer W held by the substrate holding section 31 (usually the back surface of the wafer W on which no devices are formed). do. The second processing fluid supply section 50 has one or more (two in the illustrated example) back surface nozzles 51A and 51B that discharge processing fluid toward the lower surface (second surface) of the wafer W. As schematically shown in FIG. 2, a processing liquid supply pipe 52 extends vertically inside the hollow support section 32. The upper end openings of each of the two channels extending vertically within the processing liquid supply pipe 52 serve as back nozzles 51A and 51B. The processing liquid supply pipe 52 is installed in the support column 32 so that it can maintain a non-rotating state even when the substrate holding section 31 and the support column 32 are rotating.

The back nozzle 51A (heated fluid nozzle) is supplied with temperature control DIW (pure water) for controlling the temperature of the wafer W from the temperature control DIW supply mechanism 53A. The back nozzle 51A and the temperature control DIW supply mechanism 53A constitute a heating fluid (temperature control fluid) supply mechanism. Cooling CDIW (DIW at room temperature) for cooling the wafer W is supplied to the back nozzle 51B from a CDIW supply mechanism 53B (shown only in FIG. 2). The back nozzle 51B and the CDIW supply mechanism 53B constitute a cooling fluid supply mechanism. The CDIW supply mechanism 53B may have, for example, a generally known configuration similar to the processing fluid supply mechanism 43 for the surface nozzle 41 briefly described above.

In this specification, DIW at room temperature (for example, 24° C.) is referred to as “CDIW” to distinguish it from “HDIW” which is heated DIW.

Next, the configuration of the temperature control DIW supply mechanism 53A for the back nozzle 51A will be described with reference to FIG. One temperature control DIW supply mechanism 53A is provided for each of the plurality of processing units 16 (16-1, 16-2, 16-3, . . . ). The configurations of each temperature control DIW supply mechanism 53A are substantially the same.

The substrate processing system 1 includes an HDIW main pipe 23 connected to an HDIW supply source, and a CDIW main pipe 24 connected to a CDIW supply source. The main pipes 23 and 24 supply HDIW and CDIW to all of the plurality of processing units 16 included in one substrate processing system 1 . The HDIW main pipe 23 is provided with a temperature sensor 25, and the CDIW main pipe 24 is provided with a temperature sensor 26.

The HDIW supply source and the CDIW supply source are most commonly the factory power of a semiconductor device manufacturing factory where the substrate processing system 1 is installed. However, for example, the HDIW supply source may be a tank that is provided as a component of the substrate processing system 1 and stores HDIW. The tank is supplied with DIW from a factory supply source of HDIW and a source of CDIW. In this case, a circulation pipe connected to the tank and equipped with a pump and a heater corresponds to the HDIW main pipe 23. The source of HDIW may be a hot water generator that heats and delivers DIW supplied from the source of HDIW as factory power and the source of CDIW.

The temperature control DIW supply mechanism 53A has a main pipe line 531 (heated fluid line) branched from the HDIW main pipe 23. The main pipeline 531 includes, in order from the upstream side, a flow meter 532, a constant pressure valve 533, an on-off valve 534, a first merging point 535, a second merging point 536, a first branch point 537, an on-off valve 538, and a second branch point 539. is provided. The downstream end of the main pipe line 531 is connected to the back nozzle 51A via a flow path in the processing liquid supply pipe 52.

The flow meter 532 and the constant pressure valve 533 constitute a flow rate adjustment section that adjusts the flow rate of HDIW flowing through the main pipe 531. Constant pressure valve 533 has a pilot port (details not shown). The constant pressure valve 533 operates so as to realize a secondary side pressure according to an operating pressure (air pressure) supplied to the pilot port from an electropneumatic regulator (not shown). The operating pressure supplied to the pilot port of the constant pressure valve 533 is feedback-controlled by a control device (control device 4 in FIG. 1 or its subordinate controller) so that the flow rate detected by the flow meter 532 becomes a desired value (set value). Ru.

The temperature control DIW supply mechanism 53A further includes a diluent pipe line 540 branched from the CDIW main pipe 24. The diluent pipe 540 branches into a first branch diluent pipe 542 and a second branch diluent pipe 543 at a branch point 541 . A throttle 544 and an on-off valve 545 are provided in the first branch diluent pipe 542 . A throttle 546 and an on-off valve 547 are provided in the second branch diluent pipe 543 . In the illustrated example, the throttles 544 and 546 are configured as orifices (fixed throttles) with check valves. The first branch diluent pipe line 542 and the second branch diluent pipe line 543 are connected to the main pipe line 531 at a first confluence point 535 and a second confluence point 536, respectively.

A flow meter 548 and a constant pressure valve 549 are provided upstream of the branch point 541 of the diluent pipe line 540. Flow meter 548 and constant pressure valve 549 have the same configuration and function as flow meter 532 and constant pressure valve 533.

A first drain line 550 branches off from the main conduit 531 at a first branch point 537 . The first drain line 550 is provided with an on-off valve 551, a temperature sensor 552, and a throttle 553 (in the illustrated example, an orifice (fixed throttle) with a check valve) in this order from the upstream side.

A second drain line 554 branches off from the main conduit 531 at a second branch point 539 . The second drain line 554 is provided with an on-off valve 555 and a throttle 556 (in the illustrated example, an orifice (fixed throttle) with a check valve) in this order from the upstream side.

A temperature sensor 557 is provided downstream of the second branch point 539 of the main pipe 531 .

When the HDIW supply source and the CDIW supply source are factory power, the temperature of the HDIW flowing through the HDIW main pipe 23 is, for example, 70°C, and the temperature of the CDIW flowing through the CDIW main pipe 24 is, for example, 24°C. This temperature fluctuates somewhat due to factors such as fluctuations in the outside temperature and the temperature inside the clean room, so it is monitored by temperature sensors 25 and 26.

As will be described later, HDIW for temperature control is supplied from the back surface nozzle 51A to the back surface of the wafer W with the main purpose of controlling the temperature of the wafer W. The temperature control DIW supply mechanism 53A can supply only HDIW or a mixed solution of HDIW and CDIW to the back surface of the wafer W from the back nozzle 51A. The temperature of the DIW supplied to the wafer W from the back nozzle 51A is determined by the mixing ratio of HDIW and CDIW (the flow rate of HDIW flowing into the main pipe 531 and the diluent flowing into the main pipe 531 via the diluent pipe 540 (542, 543)). This can be adjusted by changing the ratio (to the flow rate of inflowing CDIW).

As an example, assume that the flow rate of DIW to be supplied to the back surface of the wafer W from the back nozzle 51A is 1500 ml/min, and the temperature is 65°C. In this case, it can be easily determined by calculation that the flow rate of HDIW at 70°C should be 1340 ml/min and the flow rate of CDIW at 24°C should be 160 ml/min.

The control device 4 performs the above calculation. The control device 4 then provides the calculated HDIW flow rate to the HDIW flow rate feedback control system, which includes a flow meter 532, a constant pressure valve 533, and an electro-pneumatic regulator (not shown), as a set value (target value) SV. Similarly, the control device 4 provides the calculated CDIW flow rate to a CDIW flow rate feedback control system consisting of a flow meter 548, a constant pressure valve 549, and an electro-pneumatic regulator (not shown) as a set value (target value) SV, and It also outputs a signal specifying the opening/closing valve (545 or 547) of the branch diluent pipe (542 or 543) to be opened.

In addition, in the above-mentioned HDIW flow rate feedback control system and CDIW flow rate feedback control system, the flow rate detected by the flow meters 532, 548 is the measured value PV, and the operating pressure given to the constant pressure valves 533, 549 from the electropneumatic regulator is the operating amount MV. It is. The control device 4 adjusts the manipulated variable MV according to the deviation of the measured value PV from the set value SV.

In order to expand the mixing ratio range (maximum value/minimum value ratio), the opening area of the throttle 544 of the first branch diluent pipe 542 (first low-temperature fluid line) is larger than that of the second branch diluent pipe 543. The opening area of the aperture 546 (second low temperature fluid line) is set to be significantly larger. Therefore, by selectively opening either the on-off valve 545 of the first branch diluent pipe line 542 or the on-off valve 547 of the second branch diluent pipe line 543, the flow rate can be realized by the constant pressure valve 549 alone. It is possible to realize a flow rate range that is significantly wider than the range (ratio of maximum flow rate/minimum flow rate), and to adjust the flow rate with high precision.

The number of branch diluent pipes (542, 543, . . . ) is not limited to the two illustrated, and may be three or more. In this case, each branch diluent pipe is connected in parallel to the main pipe 531, and each branch diluent pipe has an on-off valve (545, 547, . . . ) and a throttle (544, 546, . . . ). provided. From the viewpoint of expanding the range of the mixing ratio, it is preferable that the aperture areas of the apertures are different from each other.

The first drain line 550 is used for an operation for discarding DIW without supplying it to the wafer W (also called "dumping" or "dummy dispensing") until the temperature stabilizes.

The second drain line 554 is used to discard DIW remaining in the back nozzle 51A, the flow path in the processing liquid supply pipe 52 communicating with the back nozzle 51A, and the pipe line in the vicinity thereof. Thereby, it is possible to prevent DIW whose temperature is not controlled from being discharged immediately after the discharge of the temperature control DIW from the back nozzle 51A is started.

The temperature control DIW supply mechanism 53A can also be operated to discharge CDIW (CDIW not mixed with HDIW) alone from the back nozzle 51A. In this case, it is also possible to omit the back nozzle 51B and the CDIW supply mechanism 53B. However, if this is done, the temperature of the back nozzle 51 and the conduit connected thereto becomes unstable, so the back nozzle 51B and the CDIW supply mechanism 53B are provided separately from the back nozzle 51A and the temperature control DIW supply mechanism 53A. It is preferable to

Next, the liquid processing performed on the wafer W in the processing unit 16 will be explained with reference to FIGS. 3 to 8. The wafer W is held in a horizontal position by the substrate holding/rotating mechanism 30 and rotated around the vertical axis so that the surface to be processed is the upper surface. The rotation of the wafer W continues until the series of steps are completed.

In the following description of liquid processing, unless otherwise specified, the landing point of the processing liquid supplied from the front nozzle 41 to the surface of the wafer W is at or near the center of rotation of the wafer W. If the processing liquid supplied from the front nozzle 41 to the surface of the wafer W lands on the wafer periphery, this fact shall be described each time the front nozzle 41 is scanned.

[Wafer temperature raising process]
First, a wafer temperature raising step (substrate temperature raising step) is performed to raise the temperature of the wafer W to a temperature suitable for liquid processing. The wafer temperature raising process is performed by supplying a temperature regulating fluid (heated fluid) to the back surface of the wafer W, which is different from the chemical liquid used in the main treatment process (chemical liquid treatment process), which will be described later. The temperature control fluid is supplied by a temperature control fluid supply section (heated fluid supply section) that includes a back nozzle 51A, a temperature control DIW supply mechanism 53A, and the like.

The temperature regulating fluid is preferably inexpensive and has a large heat capacity, and the most suitable temperature regulating fluid is water. However, the temperature regulating fluid may be a fluid other than water (DIW), such as a gas (specifically, heated nitrogen gas, for example).

Prior to the wafer temperature raising process, the on-off valve 555 is opened while the on-off valve 538 is closed, and the DIW remaining between the branch point 539 and the back nozzle 51A is discarded via the second drain line 554. be done.

On the other hand, while the on-off valve 551 is open, the on-off valve 534 is opened and HDIW flows into the main pipe 531 at a controlled flow rate, and the on-off valve 545 or the on-off valve 547 is opened to achieve a controlled flow rate. The CDIW then flows into the main conduit 531 via a junction 535 or 536. At this time, as explained earlier, the HDIW flow rate calculated by the control device 4 is given to the HDIW flow rate feedback control system as an initial setting value, and the CDIW flow rate calculated by the control device 4 is given to the CDIW flow rate feedback control system as an initial setting value. given to the control system.

HDIW and CDIW are mixed in the main pipe 531 to generate temperature control DIW. A mixing promoting device, such as an in-line mixer, may be provided between the second confluence point 536 and the first branch point 537 to facilitate mixing.

Immediately after the generation of DIW for temperature control starts, both the flow rate and the temperature tend to be unstable. The temperature instability is mainly due to the fact that the pipe (particularly the main pipe 531) before the HDIW flows is cold. Therefore, the on-off valve 551 is opened while the on-off valve 538 is closed, and the temperature control DIW immediately after the start of generation is discarded via the first drain line 550 (dummy dispense). The temperature of the temperature control DIW flowing through the first drain line 550 is monitored by a temperature sensor 552.

When the temperature has stabilized after a predetermined period of time has passed since the on-off valve 551 was opened, the control device 4 controls the temperature so that the detected value of the temperature sensor 552 becomes the target temperature based on the detected value of the temperature sensor 552. The (initial) set value (SV) of the HDIW flow rate and the (initial) set value (SV) of the CDIW flow rate may be corrected. In other words, if the detected value of the temperature sensor 552 does not rise to the target value, the HDIW flow rate is corrected by increasing the HDIW flow rate set value (SV) and decreasing the CDIW flow rate set value (SV), for example. And feedback control of the CDIW flow rate can be continued.

When the temperature detected by the temperature sensor 552 stabilizes at the target value, the on-off valve 551 is closed and the on-off valve 538 is opened. The on-off valve 555 may be closed immediately after the discharge of residual DIW via the second drain line 554 is completed, or may be closed at the same time as the on-off valve 551 is closed. As a result, the temperature control DIW at a predetermined temperature is discharged from the back nozzle 51A at a predetermined flow rate toward the center of the back surface of the wafer W (at or near the center of rotation of the wafer). The discharge flow rate of the temperature control DIW from the back nozzle 51A can be, for example, 1500 ml/min.

When CDIW is not mixed with HDIW and is supplied from the back nozzle 51A in the wafer temperature raising process, first, the on-off valve 551 is opened with the on-off valves 545, 547, and 538 closed. Further, the on-off valve 555 is opened to discharge the liquid remaining downstream from the branch point 539 in advance. Then, the HDIW that has flowed into the main pipe line 531 from the HDIW trunk pipe 23 flows into the first drain line 550. At this time, the temperature of HDIW (DIW for temperature control) flowing through the first drain line 550 is monitored by the temperature sensor 552. When the detected value of temperature sensor 552 increases and becomes stable, on-off valves 551 and 555 are closed, and on-off valve 538 is opened. As a result, HDIW starts to be ejected from the back nozzle 51A. At this point, the portion of the main pipe 531 upstream of the branch point 537 is sufficiently warmed, so the temperature of the HDIW discharged from the back nozzle 51A stabilizes in a relatively short time after discharge starts.

The wafer W has started rotating before the temperature control DIW is discharged from the back nozzle 51A. As shown in FIG. 4A, the temperature control DIW supplied to the center of the back surface of the wafer W flows toward the peripheral edge of the wafer W due to centrifugal force and is separated from the wafer W. At this time, the back surface of the wafer W is covered with a liquid film of temperature control DIW. The temperature of the wafer W is increased by being heated by the temperature control DIW.

The rotational speed of the wafer W in the wafer temperature raising process is set to an appropriate rotational speed such as 200 rpm or higher, which ensures that the temperature control DIW supplied to the center of the backside of the wafer W uniformly covers the inside of the backside of the wafer W. The rotation speed can be set as follows. Note that if the rotation speed of the wafer W is made too high, the temperature control DIW scattered outside the wafer W will violently collide with the collection cup 60, and a large amount of DIW mist will float around the wafer W, which is undesirable. . Furthermore, if the rotational speed of the wafer W is made too high, the periphery of the wafer having a high circumferential speed tends to cool down, which impairs the in-plane uniformity of the wafer temperature, which is not preferable. In consideration of the above, it is preferable to set the rotation speed of the wafer W in the wafer temperature raising process.

Note that the temperature control DIW is discharged from the back nozzle 51A after the start of the wafer temperature raising process until before the start of the wafer temperature lowering process. The temperature of the temperature control DIW discharged from the back nozzle 51A can be monitored by the temperature sensor 557. Based on the detection result of the temperature sensor 557, the HDIW flow rate set value (SV) and the CDIW flow rate set value (SV) as described above can be corrected. This correction can also be used when lowering the temperature of the temperature control DIW discharged from the back nozzle 51A from 70°C to 52°C, as will be described later.

In the wafer temperature raising step, as shown in FIGS. 4B and 4C, DIW for temperature control may also be supplied to the surface of the wafer W. In this case, it is preferable to perform dummy dispensing before supplying the temperature control DIW to the surface of the wafer W to sufficiently warm the temperature control DIW supply surface nozzle 41 and the conduit connected thereto.

In FIG. 4B, DIW for temperature control is supplied only to the central part of the surface of the wafer W at a relatively large flow rate from the surface nozzle 41 for supplying DIW for temperature control (hereinafter also referred to as "surface temperature control nozzle 41A" for simplicity). Supplied. The temperature control DIW supplied to the center of the wafer surface flows toward the peripheral edge of the wafer W due to centrifugal force, and is separated (scattering) to the outside of the wafer W. At this time, the entire surface of the wafer W is covered with a liquid film of temperature control DIW. The wafer W is also heated by the temperature control DIW supplied to the surface, and its temperature increases. Thereby, the temperature of the wafer W can be raised more quickly than in the case of FIG. 4A.

In FIG. 4C, the temperature control DIW is supplied only to the peripheral edge of the surface of the wafer W from the surface temperature control nozzle 41A at a relatively small flow rate. At this time, for example, the surface temperature control nozzle 41A may be reciprocated in the radial direction to repeatedly change the radial position of the point of contact of the temperature control DIW onto the surface of the wafer W. At this time, on the surface of the wafer W, only the ring-shaped area at the peripheral edge is covered with the liquid film of the temperature control DIW. In the case of FIG. 4C, since the peripheral edge of the wafer W, which tends to get cold easily, is locally heated, the temperature uniformity within the wafer surface can be further improved. Instead of reciprocating the surface temperature control nozzle 41A, the temperature control DIW may be discharged while the surface temperature control nozzle 41A is fixed at the same position (for example, the position shown in FIG. 4C).

In the wafer temperature raising process, regardless of which of the procedures shown in FIGS. 4A, 4B, and 4C is adopted, the wafer temperature in the main processing step (also referred to as "wafer temperature during main processing", which will be described later) is, for example, 50°C. It is preferable to raise the temperature of the wafer W to a higher temperature (for example, 70° C.). It is possible to shorten the time required for the temperature of the wafer W to stabilize at the wafer temperature during the main processing by raising the temperature once to the first temperature higher than the wafer temperature during the main processing and then lowering the temperature. This has also been confirmed through actual test runs.

[Liquid film formation process and main treatment process]
Next, a liquid film forming step of forming a liquid film of the prewetting liquid over the entire surface of the wafer W, and a main treatment step (chemical treatment step) of treating the surface of the wafer W with a chemical solution are performed. The pre-wet liquid may be the same chemical solution as the chemical solution used in the main treatment step described below, or may be another liquid (for example, DIW, IPA (isopropyl alcohol), etc.) that can be easily replaced with the chemical solution used in the main treatment step described later. There may be.

Even after the wafer temperature raising step in FIG. 4A, FIG. 4B, or FIG. 4C is completed, the temperature control DIW continues to be discharged onto the back surface of the wafer W from the back nozzle 51A. However, the temperature of the temperature control DIW discharged from the back nozzle 51A is lowered to approximately the same temperature (for example, 52° C.) as the wafer temperature during the main processing by adjusting the mixing ratio of CDIW. As a result, the temperature of the wafer W decreases toward the wafer temperature during the main processing.

In the wafer temperature raising process, as shown in FIG. 4A, when the temperature control DIW is not being supplied to the surface of the wafer W, the surface nozzle 41 for chemical supply (hereinafter also referred to as "surface chemical nozzle 41B" for convenience) is used. ), the same room temperature chemical liquid as the chemical liquid used in this treatment step is supplied as the pre-wet liquid (see FIG. 5A). The room temperature chemical solution is supplied from the surface chemical solution nozzle 41B to the center of the surface of the wafer W (at or near the center of rotation of the wafer) at a first discharge flow rate while the wafer W is rotated at a first rotation speed.

At this time, in order to quickly spread the chemical over the entire surface of the wafer W, it is preferable that the first rotational speed is relatively high (for example, about 800 rpm). Further, the first discharge flow rate may be relatively large (for example, about 1000 ml/min). By making the first discharge flow rate relatively large, even if the rotational speed of the wafer W is made relatively high, the entire surface of the wafer W can be reliably covered with a liquid film of the chemical solution. Furthermore, by making the first discharge flow rate relatively large, the chemical solution supplied to the surface of the wafer W, which is at a relatively high temperature (for example, about 70° C.) at the start of the liquid film forming process, evaporates, creating a dry region. This can be reliably prevented.

In addition, in the case of conditions in which it is difficult to form a uniform liquid film, it is particularly preferable to set the first rotational speed and the first discharge flow rate to be relatively large in order to prevent fingering. Specifically, for example, a case may be considered in which a chemical liquid with low wettability to the wafer W or a highly viscous chemical liquid is used.

In the wafer temperature raising step, if DIW for temperature control is also being supplied to the wafer surface from the surface temperature control nozzle 41A as shown in FIG. 4B or 4C, the discharge of DIW for temperature control from the surface temperature control nozzle 41A is stopped. do. Then, the liquid film forming step is executed by supplying the same room temperature chemical as the chemical used in the main processing step to the center of the surface of the wafer W as a pre-wet liquid from the surface chemical nozzle 41B. In this case as well, the state shown in FIG. 5A is reached.

When moving from the state shown in FIG. 4B or 4C to the liquid film forming step, in order to prevent the uneven pattern formed on the surface of the wafer W from collapsing, the chemical solution is applied before the temperature control DIW is removed from the pattern recess. It is preferable to supply it to the surface of the wafer W.

At this time, it is preferable to switch between the first processing liquid (DIW for temperature control in this case) that is supplied first and the second processing liquid (chemical solution here) that is supplied later. First, the process starts from a state in which the first processing liquid is applied from the first surface nozzle 41 (here, the surface temperature control nozzle 41A) to the rotation center of the surface of the wafer W. From this state, the second processing liquid discharged from the second surface nozzle 41 (here, the surface chemical liquid nozzle 41B) located close to the first surface nozzle 41 is directed to a position slightly away from the rotation center of the surface of the wafer W. Let the liquid adhere to the liquid. Thereafter, the first and second surface nozzles 41 are arranged so that the point of contact of the first processing liquid moves away from the center of rotation of the wafer, and the point of contact of the second processing liquid approaches the center of rotation of the wafer. move in conjunction with each other. When the landing point of the second processing liquid reaches the rotation center of the wafer, the discharge of the first processing liquid from the first surface nozzle 41 is stopped. In this case, the end of the period for supplying the first processing liquid to the wafer surface and the beginning of the period for supplying the chemical solution overlap. Hereinafter, in this specification, for the sake of simplicity, this processing liquid switching method will also be referred to as an "overlap switching method."

This overlap switching method may be performed while moving the first surface nozzle (41) and the second surface nozzle (41) carried by a common nozzle arm (42) so that the above relationship is established. good. Instead, a first surface nozzle 41 carried on a first nozzle arm (42) and a second surface nozzle (41) carried on a second nozzle arm (42) different from the first nozzle arm (42) are used. ) may be executed while being moved so that the above relationship is established.

If there is no problem even if a configuration is adopted in which the first processing liquid (here, DIW for temperature control) supplied first and the second processing liquid (here, chemical liquid) supplied later are discharged from the same surface nozzle 41, The processing liquid can be switched as follows. That is, the first processing liquid supply mechanism and the second processing liquid supply mechanism are connected in parallel to one surface nozzle 41. Then, almost at the same time as the supply of the first processing liquid from the first processing liquid supply mechanism to the surface nozzle 41 is stopped, the supply of the second processing liquid from the second processing liquid supply mechanism to the surface nozzle 41 is started. By doing so, the processing liquid can be switched without interruption of the supply of the processing liquid to the surface of the wafer W. Using two separate surface nozzles (first surface nozzle 41 and second surface nozzle 41), immediately after stopping the discharge of the first treatment liquid from the first surface nozzle 41, the second treatment is performed from the second surface nozzle 41. You may also start discharging the liquid. Note that, hereinafter, in this specification, for the sake of simplicity, this processing liquid switching method will also be referred to as a "sequential switching method."

In the liquid film forming step, supplying DIW for temperature adjustment at a temperature approximately equal to the wafer temperature during main processing to the back surface of the wafer W from the back nozzle 51A, and supplying a room temperature chemical solution to the front surface of the wafer W from the front nozzle 41. As a result, the wafer W is cooled, and the temperature of the wafer W decreases to the wafer temperature during the main processing.

In addition, in the liquid film forming step and the main treatment step, since the chemical at room temperature (for example, 25° C.) is continuously supplied to the front surface of the wafer W from the front chemical nozzle 41B, the chemical at room temperature (for example, 25° C.) is supplied to the back surface of the wafer W from the back nozzle 51A. The temperature of the temperature control DIW is set to a temperature slightly higher (eg, 52° C. to 55° C.) than the wafer temperature (eg, 50° C.) during the main processing. By doing so, the temperature of the wafer W (the temperature of the interface between the wafer surface and the chemical solution) can be maintained at the wafer temperature during the main processing. The temperature of the temperature control DIW supplied to the back surface of the wafer W in this processing step includes the temperature of the chemical solution supplied to the front surface of the wafer W in this processing step, the flow rate of the chemical solution, the specific heat of the chemical solution, the rotation speed of the wafer W, the chamber The temperature can be determined in consideration of factors that may affect the temperature of the wafer W, such as the temperature inside the chamber 20 and the flow rate of the downflow inside the chamber 20.

The liquid film forming process is a process that not only forms a uniform liquid film of the chemical solution over the entire surface of the wafer W, but also stabilizes the temperature of the wafer W by lowering it to the wafer temperature during the main processing, so it is called a "stabilization process". ” can also be considered. In this stabilization step, the atmosphere within the chamber 20 may be adjusted to the atmosphere required in this treatment step. For example, by supplying nitrogen gas into the chamber 20 from the FFU 21, the atmosphere within the chamber 20 may be made to have a low oxygen concentration and low humidity. In the stabilization step, the rotational speed of the wafer W is changed from the first rotational speed to a second rotational speed, which is the rotational speed of the wafer W in the main processing step, or to an appropriate rotational speed that is higher than the second rotational speed and lower than the first rotational speed. It may be lowered to

When the temperature of the wafer W becomes stable at the wafer temperature during the main processing, the main processing step is started. In transitioning to the main processing step, while the rotational speed of the wafer W is set to the above-mentioned second rotational speed, temperature control DIW (this is, for example, 52° C.) is continuously discharged from the backside nozzle 51A, and then A chemical solution at room temperature (for example, 25° C.) is discharged from the chemical solution nozzle 41B onto the surface of the wafer W (see FIG. 6).

By lowering the rotational speed of the wafer W (setting it to the second rotational speed), the tendency for the peripheral edge of the wafer W to cool easily is alleviated. Thereby, the uniformity of processing results within the wafer surface can be improved. Furthermore, by lowering the rotational speed of the wafer W, it is possible to maintain the liquid film even if the discharge flow rate of the chemical liquid discharged from the surface chemical liquid nozzle 41B is reduced.

The second discharge flow rate, which is the flow rate of the chemical liquid discharged from the surface chemical liquid nozzle 41B in this treatment process, may be smaller than the first discharge flow rate, which is the flow rate of the chemical liquid discharged from the surface chemical liquid nozzle 41 in the liquid film forming process. preferable. Thereby, the amount of consumption of the chemical solution can be reduced. Particularly when expensive chemicals are used, reducing the consumption of chemicals is beneficial in reducing processing costs. Note that even if the second discharge flow rate is small, the wafer W can be maintained at a temperature that ensures an appropriate reaction between the wafer W and the chemical solution.

As the surface chemical liquid nozzle 41B, a surface chemical liquid nozzle for large flow rate and a surface chemical liquid nozzle for small flow rate may be provided. Alternatively, a chemical liquid supply line for large flow rate and a chemical liquid supply line for small flow rate that can be selectively switched may be connected to a single surface chemical liquid nozzle 41B. By doing so, the flow rate of the chemical liquid discharged from the surface chemical liquid nozzle 41B can be quickly switched from the first discharge flow rate to the second discharge flow rate.

This processing step is completed by continuing to rotate the wafer W at the second rotation speed and supplying the chemical solution at the second discharge flow rate for a predetermined period of time (for example, about 30 seconds). Note that in this processing step, since the surface of the wafer W itself is sufficiently heated, the temperature of the interface between the surface of the wafer W and the chemical solution is sufficiently high. Therefore, the reaction between the surface of the wafer W and the chemical solution proceeds sufficiently.

In one embodiment, the time required for the liquid film forming step is sufficiently shorter than the time required for the main treatment step, for example, 5 seconds or less, and specifically, for example, about 2 to 3 seconds. Therefore, even if the discharge flow rate of the chemical solution per unit time in the liquid film forming process (first discharge flow rate) is larger than the discharge flow rate of the chemical solution per unit time in the main treatment process (second discharge flow rate), the total amount of the chemical solution used There is no major impact on

In this processing step, the surface chemical liquid nozzle 41B may be always positioned directly above the center of the wafer W so that the chemical liquid always lands on the center of the wafer W (front surface nozzle fixed). Alternatively, this processing step may be performed while moving the surface chemical liquid nozzle 41B to move the point where the chemical liquid lands on the surface of the wafer W (surface nozzle scan). When the discharge flow rate (second discharge flow rate) of the chemical liquid from the surface chemical liquid nozzle 41B in this processing step is made small, the scanning conditions of the surface chemical liquid nozzle 41B (scan width , scan speed, scan range).

When surface nozzle scanning is performed in this treatment step, surface nozzle scanning may be performed in the liquid film formation step (stabilization step) under the same conditions as in this treatment step.

In the liquid film forming step and the main treatment step, the chemical solution is supplied at room temperature, so there is no need to heat the chemical solution in advance. If the chemical solution is kept heated for a long time, the chemical solution may be consumed due to evaporation, deterioration, etc. At room temperature, there is no consumption of the chemical solution, or even if consumption occurs, the degree of consumption is significantly lower than when heated. This is particularly advantageous from the viewpoint of reducing processing costs when expensive chemical solutions are used. There are also chemical solutions that, when heated, generate vapors (gases) that are flammable or harmful to the human body. When such a chemical solution is used, costs for ensuring safety can be reduced by not heating the chemical solution.

In order to prepare a heated chemical solution in advance, a heated chemical solution supply system is equipped with a chemical storage tank, a circulation pipe connected to the chemical storage tank, and equipment such as a pump and a heater installed in the circulation pipe. system is required. On the other hand, a chemical liquid supply system for supplying a chemical liquid at room temperature requires fewer components than a heated chemical liquid supply system, which contributes to reducing the cost of the substrate processing apparatus.

Note that the supply temperature of the chemical solution is not limited to room temperature, and may be higher than room temperature as long as the temperature is such that consumption of the chemical solution does not pose a problem.

As one of the processes in which the technology according to the present embodiment is most effective, an organic chemical treatment process included in the BEOL process of the semiconductor manufacturing process is exemplified. In this organic chemical treatment step, an expensive organic chemical is supplied to the wafer in a heated state. With the miniaturization of patterns in recent years, the level of cleanliness required of organic chemicals has increased, and it has become impossible to recover and reuse organic chemicals once supplied to a wafer. For this reason, it is necessary to make organic chemical solutions disposable. In order to reduce processing costs, there is a need to reduce the amount of chemical liquid required to process one wafer. In this embodiment, the chemical liquid treatment step (main treatment step) is performed while heating the back surface of the wafer with the temperature control DIW. There is no need to supply organic chemical liquid at a large flow rate. In addition, in the conventional technique in which the back surface of the wafer is not heated by DIW for temperature control, heated organic chemical liquid is supplied at a large flow rate (for example, about 1500 ml/min). As a result, the entire wafer is quickly heated to a temperature necessary for the reaction between the chemical solution and the wafer, and the tendency for the temperature of the peripheral portion of the wafer to decrease is alleviated. In the case of the organic chemical liquid treatment step included in the BEOL process, according to the present embodiment, the discharge flow rate of the organic chemical liquid is, for example, about 150 ml/min even when performing the liquid film forming process using the organic chemical liquid, and the chemical liquid treatment In the process (main treatment process), it is equal to or even less than that. In other words, according to this embodiment, the amount of organic chemical liquid used can be reduced to about 1/10 of that of the prior art. Furthermore, in this embodiment, the temperature required for the reaction between the chemical solution and the wafer is maintained by heating the back surface of the wafer W with the temperature control DIW, so the organic chemical solution is heated in advance as described above. There's no need. Therefore, consumption of the expensive organic chemical can be suppressed, and the amount of organic chemical used can be reduced.

Note that the surface chemical liquid nozzle 41B and the chemical liquid supply mechanism (processing fluid supply mechanism) 43 connected thereto constitute a chemical liquid supply section.

[Modified embodiment of liquid film formation step and main treatment step]
When the wafer temperature raising step of FIG. 4B or 4C is adopted, and the DIW for temperature control is easily replaced by a chemical solution (for example, when the DIW and the chemical solution are compatible), the wafer temperature increase process shown in FIG. The temperature control DIW supplied to the surface of the wafer W in the hot process can be used as a prewetting liquid. The ejection flow rate and temperature transition of the temperature control DIW supplied from the backside nozzle 51A to the backside of the wafer W may be the same as in the case where the wafer temperature raising step of FIG. 4A described above is adopted.

When the wafer temperature raising process shown in FIG. 4B is adopted, after the wafer temperature raising process is completed, the surface temperature adjusting nozzle 41A continues to be positioned directly above the center of the wafer W, and discharge from the surface temperature adjusting nozzle 41A is continued. The temperature of the temperature control DIW is lowered from the first temperature (eg, 70° C.) in the wafer temperature raising process to a lower second temperature (eg, 52° C.) (see FIG. 5B). As a result, the temperature of the wafer W decreases so as to approach the wafer temperature during the main processing (for example, 50° C.).

When the wafer temperature raising process shown in FIG. 4C is adopted, after the wafer temperature raising process is completed, the surface temperature control nozzle 41A is moved directly above the center of the wafer W, and the temperature emitted from the surface temperature control nozzle 41A is The temperature of the prepared DIW may be reduced to a second temperature (eg, 52° C.) (see FIG. 5C).

In any of the above cases, DIW for temperature control is used as the pre-wet liquid. In other words, in this case, the wafer temperature raising process can be considered to also serve as the liquid film forming process, and the process of discharging the temperature control DIW from the surface temperature control nozzle 41A at the second temperature (for example, 52°C) is the stabilization process. It can also be considered as

The processing fluid supply mechanism 43 that supplies DIW for temperature control to the surface temperature control nozzle 41A has the same configuration as the DIW supply mechanism 53A for temperature control that supplies DIW for temperature control to the back nozzle 51A (that is, the mixing ratio of HDIW and CDIW is (a configuration in which the temperature is adjusted by adjusting the temperature).

When the temperature of the wafer W stabilizes at the wafer temperature during the main processing, the discharge of the temperature control DIW from the surface temperature control nozzle 41A is stopped, and the discharge of the chemical liquid from the surface chemical liquid nozzle 41B is started, and the main processing step is started ( (see Figure 6). In this case, the above-mentioned overlap switching method may be used to switch the supplied processing liquid from the temperature control DIW to the chemical liquid. The processing liquid supplied may be switched from the temperature control DIW to the chemical liquid using a sequential switching method.

Slightly before the temperature of the wafer W stabilizes at the wafer temperature during main processing, the discharge of the temperature control DIW from the surface temperature control nozzle 41A may be stopped, and the discharge of the chemical liquid from the surface chemical liquid nozzle 41B may be started. .

In this processing step, the landing point of the chemical liquid discharged from the surface chemical liquid nozzle 41B can be at or near the center of rotation of the wafer surface. During this treatment process, the landing point of the chemical liquid may be moved by scanning the surface chemical liquid nozzle 41B.

Also in the above-described modified embodiment, it is preferable that the number of rotations of the wafer W (second number of rotations) in this processing step is smaller than the number of rotations of the wafer W (first number of rotations) in the liquid film forming step. This can reduce the tendency for the peripheral edge of the wafer W to become easily cold.

Also in the modified embodiment described above, the discharge flow rate of the chemical liquid from the surface chemical liquid nozzle 41B in this treatment step may be the same as the second discharge flow rate in the embodiment described above.

This processing step is completed by supplying the chemical liquid to the surface of the wafer W for a predetermined period of time from the surface chemical liquid nozzle 41B.

[Wafer temperature cooling process (substrate temperature cooling process)]
The wafer temperature lowering step is performed by supplying a temperature regulating (cooling) fluid to the back surface of the wafer W, which is different from the chemical used in the main treatment step (chemical treatment step). The temperature regulating fluid is preferably inexpensive and has a large heat capacity, and the most suitable temperature regulating fluid is CDIW.

The wafer temperature cooling step is executed as follows. After this processing step is completed, the discharge of temperature control DIW from the back nozzle 51A is stopped, and CDIW is discharged onto the back surface of the wafer W from the back nozzle 51B. As a result, the temperature of the wafer W decreases, and the reaction rate between the object to be removed (or the object to be reacted) on the surface of the wafer W and the chemical solution decreases. Discharge of CDIW from the back nozzle 51B continues until the rinsing process is completed.

[Rinse process]
In parallel with the ejection of CDIW from the back nozzle 51B, a rinsing liquid is supplied to the front surface of the wafer W from the front nozzle 41 for supplying a rinsing liquid, and a rinsing process is performed on the wafer surface (see FIG. 7). Note that if the temperature of the wafer W has decreased sufficiently, the discharge of CDIW from the back nozzle 51B may be stopped.

When DIW cannot be used as the rinsing liquid, for example, when an organic solvent such as IPA is used as the rinsing liquid, the rinsing process can be performed according to the following procedure.

<First step of IPA rinsing>
In the first procedure, the supply of the chemical liquid from the surface chemical liquid nozzle 41B is stopped, and the chemical liquid is removed from the surface of the wafer W by shaking it off for a predetermined time (for example, several seconds). (Hereinafter, for convenience, it will also be referred to as the "front IPA nozzle 41C.") The discharge of IPA is started. Then, the front surface of the wafer W is rinsed by supplying IPA to the wafer W for a predetermined time from the front IPA nozzle 41C.

<Second step of IPA rinse>
In the second procedure, the above-described overlap switching method is used to switch from a state in which a chemical liquid is being discharged from the surface chemical liquid nozzle 41B to a state in which IPA is being discharged from the surface IPA nozzle 41C. Then, the front surface of the wafer W is rinsed by supplying IPA to the wafer W for a predetermined time from the front IPA nozzle 41C.

[Drying process]
After performing the IPA rinsing according to the first procedure or the second procedure, a drying process is performed. This drying process involves, for example, depositing IPA discharged from the front IPA nozzle 41C on the wafer surface while supplying a drying gas such as nitrogen gas with a low oxygen concentration and low humidity to the surface of the wafer W. This can be done by moving the point from the center of the wafer W to the periphery (see FIG. 8). The drying gas can be discharged from the surface nozzle 41 (hereinafter also referred to as "surface gas nozzle 41D" for convenience) for supplying the drying gas, and in this case, the position at which the drying gas is blown onto the wafer surface is It is preferable to move the front IPA nozzle 41C and the front gas nozzle 41D in association with each other so that the front IPA nozzle 41C and the front gas nozzle 41D are maintained slightly radially inward from the point where IPA from the front IPA nozzle 41C lands on the wafer surface.

The drying step is not limited to the one described above, and after performing the first and second steps (of IPA rinsing) described above, simply stopping the discharge of IPA from the front IPA nozzle 41C, It is also possible to dry the wafer W by shaking it off.

When using DIW as the rinsing liquid, use the surface nozzle 41 (hereinafter also referred to as "surface rinse nozzle 41E" for convenience) for supplying CDIW to the surface of the wafer W, and perform rinsing according to the following procedure. The process can be carried out.

During the drying process, the discharge of CDIW from the back nozzle 51B may be stopped. Furthermore, HDIW may be discharged from the back nozzle 51A to accelerate drying.

<DIW rinsing procedure>
Using the surface chemical liquid nozzle 41B and the surface rinse nozzle 41E, the state in which the chemical liquid is supplied to the surface of the wafer W is switched to the state in which room temperature DIW (CDIW) is supplied by the overlap switching method described above. DIW rinsing is completed by supplying CDIW from the surface rinsing nozzle 41E for a predetermined time (see FIG. 7).

Thereafter, using the front surface rinse nozzle 41E and the front surface IPA nozzle 41C, the state in which CDIW is supplied to the surface of the wafer W is switched to the state in which IPA is supplied by the above-described overlap switching method. By supplying IPA from the front surface IPA nozzle 41C for a predetermined period of time, CDIW on the surface of the wafer W is replaced with IPA.

Thereafter, a drying process similar to the drying process described above is performed.

Note that if DIW cannot be used as the rinsing liquid, cooling of the wafer W after the chemical treatment process is mainly performed by CDIW supplied to the back surface of the wafer W. Since expensive IPA is not normally supplied at a large flow rate, the contribution of IPA supplied to the surface of the wafer W to the cooling of the wafer W is small. When DIW can be used as the rinsing liquid, the wafer W can be cooled quickly by supplying CDIW at a large flow rate not only to the back surface of the wafer W but also to the front surface of the wafer W.

Upon completion of the drying process, a series of liquid treatments for one wafer W is completed. Thereafter, the wafer W is carried out from the processing unit 16.

The processing liquid present on the surface of the wafer W at the start of the drying process is not limited to IPA, and may have a low surface tension (at least a surface tension lower than that of DIW) that can prevent the pattern on the surface of the wafer W from collapsing. ) may be a solvent other than IPA. The processing liquid present on the surface of the wafer W at the start of the drying process is preferably a liquid with higher volatility than DIW.

According to the above embodiment, the temperature at the contact interface between the front surface of the wafer W and the chemical solution is controlled by supplying the temperature control DIW (HDIW, CDIW, or a mixture thereof) to the back surface of the wafer W. Therefore, even if a chemical solution to be caused to react with the surface of the wafer W at a high temperature is supplied at room temperature, the intended reaction can be achieved. As a result, it becomes possible to prevent consumption of the chemical solution, reduce the consumption amount of the chemical solution, and realize processing with high in-plane uniformity.

With reference to FIG. 9, an example of the change in wafer temperature from the wafer temperature raising process to the rinsing process will be described. In the wafer temperature raising step (S1), 70° C. HDIW is supplied to the back surface (BACK) of the wafer W as a temperature control liquid. Ten seconds after the start of the wafer temperature raising step (S1), the temperature of the wafer W reaches approximately 70°C. After that, in the liquid film forming step (S2), HDIW at 52° C. is supplied as a temperature control liquid to the back surface of the wafer W, and a chemical solution (CHM) at room temperature (25° C.) is supplied to the front surface (FRONT) of the wafer W. . Approximately 3 seconds after the start of the liquid film forming step (S2), the wafer temperature stabilizes at 50° C., which is the wafer temperature during the main processing. Thereafter, in the main treatment step (S3), that is, the chemical treatment step, HDIW at 52° C. is continuously supplied to the back surface of the wafer W, and a chemical solution (CHM) at room temperature (25° C.) is supplied to the front surface of the wafer W. However, as described above, the wafer rotation speed and the chemical liquid discharge flow rate in this processing step (S3) are set lower than in the liquid film forming step (S2). This processing is carried out for approximately 17 seconds from the main processing step (S3). After that, in the wafer temperature lowering step (S4), 24° C. CDIW is supplied to the back surface of the wafer W, and the temperature of the wafer W is lowered to room temperature in about 2 seconds. In the example of FIG. 9, CDIW at 24° C. is supplied as a rinsing liquid to the surface of the wafer W at the start of the wafer temperature lowering step (S4). This CDIW is a cooling liquid that lowers the temperature of the wafer W, and is also a rinsing liquid that washes away the chemical liquid on the surface of the wafer W. Even after the temperature of the wafer W stabilizes at room temperature, CDIW at 24° C. is continuously supplied as a rinsing liquid to the surface of the wafer W, and a rinsing step (S5) is performed. In the example of FIG. 9, the wafer temperature lowering step (S4) is also included as part of the rinsing step (S5).

In the above embodiment, different processing liquids are supplied through separate surface nozzles 41, but the present invention is not limited to this. For example, two or more types of processing liquids that do not cause problems even if supplied through the same nozzle may be supplied from one surface nozzle 41. Further, in the above embodiment, only DIW for controlling the temperature of the wafer W was supplied from the back nozzles 51A and 51B, but a configuration is also available in which other processing liquids, such as chemical solutions, can also be supplied from the back nozzle 51A. I don't mind if it is. Note that when multiple types of processing liquids are supplied from the same nozzle, a plurality of processing liquid supply mechanisms whose connections can be switched by a switching valve (or a plurality of on-off valves) are connected in parallel to one surface nozzle 41. Such configurations are well known and will not be described in detail herein.

Next, with reference to FIG. 10, an example of the piping system for HDIW and CDIW in the substrate processing system 1 will be briefly described. The processing station 3 of the substrate processing system 1 has a two-layer structure consisting of an upper layer 3A and a lower layer 3B. In FIG. 10, reference numeral 71 represents an HDIW supply source as a factory power, and reference numeral 72 represents a CDIW supply source as a factory power.

The upstream end of the HDIW conduit 711 is connected to the HDIW supply source 71 . The HDIW conduit 711 branches at a branch point 712 into a branch conduit 713A for the upper layer 3A and a branch conduit 713B for the lower layer 3B. On the upstream side of the branch point 712, the HDIW pipe line 711 is provided with an on-off valve 710 and a temperature sensor 716. The branch pipes 713A and 713B merge again at a confluence point 714 to form one HDIW pipe 711. The downstream end of HDIW conduit 711 is connected to a factory drain line (DR). A back pressure valve 715 is provided downstream of the confluence point 714.

The upstream end of the CDIW conduit 721 is connected to the CDIW supply source 72 . The CDIW conduit 721 branches at a branch point 722 into a branch conduit 723A for the upper layer 3A and a branch conduit 723B for the lower layer 3B. Upstream of the branch point 722, the CDIW conduit 721 is provided with a CO ₂ bubbler 720 and a temperature sensor 726. The branch pipes 723A and 723B merge again at a confluence point 724 to form one CDIW pipe 721. The downstream end of CDIW conduit 721 is connected to a factory drain line (DR). Orifices 727A, 727B (fixed throttles) for pressure control are provided at the most downstream parts of the branch pipes 723A, 723B (meaning the part downstream from the connection point to the most downstream processing unit 16). It is being

The branch pipe 713A (713B) corresponds to the HDIW main pipe 23 in the fluid circuit diagram of FIG. The branch pipe 723A (723B) corresponds to the CDIW main pipe 24 in the fluid circuit diagram of FIG. That is, in the example of FIG. 10, the HDIW taken out from the branch pipe 713A (713B) and the CIWD taken out from the branch pipe 723A (723B) are ) and supplied to the back nozzle 51A. The configuration of the temperature control DIW supply mechanism 53A in FIG. 10 is the same as the configuration of the temperature control DIW supply mechanism 53A in FIG. Although one temperature control DIW supply mechanism 53A is provided in each processing unit 16, only one is shown in FIG. 10 to simplify the drawing.

FIG. 11 shows another example of the HDIW piping system within the substrate processing system 1. In FIG. 11, the description of the CDIW piping system is omitted. In this example, the upstream end of an HDIW conduit 803 is connected to a HIDW supply line 801 for factory use. The HDIW conduit 803 branches at a branch point 804 into a branch conduit 805A for the upper layer 3A and a branch conduit 805B for the lower layer 3B. On the upstream side of the branch point 804, the HDIW pipe line 803 is provided with an on-off valve 817 and a temperature sensor 816. The branch pipes 805A and 805B merge again at a confluence point 806 to form one HDIW pipe 803. On the downstream side of the confluence point 806, the HDIW pipe line 803 is provided with an on-off valve 807 and a check valve 808. The downstream end of HDIW conduit 803 is connected to HIDW return line 802 as part of the factory power system. A drain pipe line 809 branches from the HDIW pipe line 803 between the confluence point 806 and the on-off valve 807 . An on-off valve 810 is provided in the drain pipe 809. During normal operation of the substrate processing system 1, the on-off valves 807 and 817 are open, and the on-off valve 810 is closed. When the operation of the substrate processing system 1 is to be stopped for the purpose of maintenance or the like, the on-off valves 807 and 817 are closed, and the on-off valve 810 is opened to discharge DIW in the conduit. In this example, unlike the example in FIG. 10, no back pressure valve is provided at the downstream end of the HDIW conduit 803.

The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The embodiments described above may be omitted, replaced, or modified in various forms without departing from the scope and spirit of the appended claims.

The substrate to be processed is not limited to a semiconductor wafer (wafer W), but may be any substrate used in the field of semiconductor device manufacturing, such as a glass substrate or a ceramic substrate.

W Substrate S1 Substrate temperature raising process S2 Liquid film forming process S3 Chemical solution treatment process S4 Substrate temperature lowering process

Claims (15)

a substrate temperature raising step of heating the substrate to increase the temperature of the substrate;
After the substrate temperature raising step, a prewetting liquid is supplied to the first surface of the substrate while heating the substrate and rotating at a first rotation speed, so that the prewetting liquid is applied to the first surface of the substrate. a liquid film forming step for forming a film;
After the liquid film forming step, a chemical solution is supplied to the first surface of the substrate while heating the substrate and rotating it at a second rotation speed lower than the first rotation speed, so that the first surface of the substrate is heated. a chemical liquid treatment step of treating with the chemical liquid;
a substrate temperature lowering step of lowering the temperature of the substrate after the chemical treatment step;
Equipped with
The substrate is heated in the substrate temperature raising step, the liquid film forming step, and the chemical treatment step by supplying a heated fluid different from the chemical to at least a second surface of the substrate on the back side of the first surface. carried out,
The temperature of the heated fluid supplied to the second surface of the substrate in the substrate temperature raising step is a first temperature higher than the target temperature of the substrate in the chemical treatment step; The temperature of the heated fluid supplied to the substrate processing method is lowered to a second temperature lower than the first temperature before the chemical treatment step is started. 2. The substrate processing method according to claim 1 , wherein heating of the substrate in the substrate temperature raising step is performed by supplying the heated fluid different from the chemical solution only to the second surface of the substrate. The heating of the substrate in the substrate temperature raising step further includes heating the first surface of the substrate at a temperature higher than the temperature of the prewetting liquid supplied to the first surface of the substrate in the liquid film forming step. 2. The substrate processing method according to claim 1, wherein the substrate processing method is carried out by supplying a heated fluid. 4. The substrate processing method according to claim 3, wherein the heated fluid supplied to the first surface of the substrate in the substrate temperature raising step is supplied only to a peripheral portion of the first surface. 4. The substrate processing according to claim 3, wherein the heated fluid supplied to the first surface of the substrate in the substrate temperature raising step is the same liquid as the prewetting liquid having a higher temperature than the prewetting liquid. Method. 5. The substrate processing method according to claim 4, wherein the heated fluid supplied to the first surface of the substrate in the substrate temperature raising step and the prewetting liquid are both DIW (pure water). 4. The substrate processing according to claim 3, wherein the heated fluid supplied to the first surface of the substrate in the substrate temperature raising step is a liquid different from the prewetting liquid and having a higher temperature than the prewetting liquid. Method. The pre- wetting liquid used in the liquid film forming step is the same liquid as the chemical liquid used in the chemical liquid treatment step, and in the liquid film forming step, the chemical liquid as the pre-wetting liquid is applied at the first flow rate. 8. The substrate processing according to claim 7 , wherein the chemical solution is supplied to the first surface of the substrate, and in the chemical solution treatment step, the chemical solution is supplied to the first surface of the substrate at a second flow rate smaller than the first flow rate. Method. 9. The substrate processing method according to claim 8, wherein the heated fluid supplied to the first surface of the substrate in the substrate temperature raising step is DIW (pure water). a substrate temperature raising step of heating the substrate to increase the temperature of the substrate;
After the substrate temperature raising step, a prewetting liquid is supplied to the first surface of the substrate while heating the substrate and rotating at a first rotation speed, so that the prewetting liquid is applied to the first surface of the substrate. a liquid film forming step for forming a film;
After the liquid film forming step, a chemical solution is supplied to the first surface of the substrate while heating the substrate and rotating it at a second rotation speed lower than the first rotation speed, so that the first surface of the substrate is heated. a chemical liquid treatment step of treating with the chemical liquid;
a substrate temperature lowering step of lowering the temperature of the substrate after the chemical treatment step;
Equipped with
The substrate temperature raising step is performed by supplying a heated fluid different from the chemical solution to the first surface and the second surface on the back side of the substrate,
In the substrate temperature raising step, the heated fluid supplied to the first surface of the substrate has a temperature higher than that of the prewetting liquid supplied to the first surface of the substrate in the liquid film forming step. A fluid heated to a high temperature,
A substrate processing method, wherein heating of the substrate in the liquid film forming step and the chemical treatment step is performed by supplying a heated fluid different from the chemical to at least a second surface of the substrate on the back side of the first surface. . a substrate temperature raising step of heating the substrate to increase the temperature of the substrate;
After the substrate temperature raising step, a prewetting liquid is supplied to the first surface of the substrate while heating the substrate and rotating at a first rotation speed, so that the prewetting liquid is applied to the first surface of the substrate. a liquid film forming step for forming a film;
After the liquid film forming step, a chemical solution is supplied to the first surface of the substrate while heating the substrate and rotating it at a second rotation speed lower than the first rotation speed, so that the first surface of the substrate is heated. a chemical liquid treatment step of treating with the chemical liquid;
a substrate temperature lowering step of lowering the temperature of the substrate after the chemical treatment step;
Equipped with
The substrate temperature raising step includes supplying the heated fluid different from the chemical solution only to the peripheral edge of the first surface of the substrate, and supplying the heated fluid different from the chemical solution to a second surface behind the first surface of the substrate. carried out by supplying said heated fluid different from
In the substrate temperature raising step, the heated fluid supplied to the first surface of the substrate has a temperature higher than that of the prewetting liquid supplied to the first surface of the substrate in the liquid film forming step. A fluid heated to a high temperature,
A substrate processing method, wherein heating of the substrate in the liquid film forming step and the chemical treatment step is performed by supplying a heated fluid different from the chemical to at least a second surface of the substrate on the back side of the first surface. . 12. The substrate processing method according to claim 1, wherein in the chemical treatment step, the chemical is supplied to the first surface of the substrate at room temperature. The substrate temperature lowering step is performed by supplying at least a fluid different from the chemical liquid to the second surface of the substrate, the temperature being lower than the target temperature of the substrate in the chemical liquid treatment step. 13. The substrate processing method according to claim 12 . a substrate holding unit that holds a substrate having a first surface and a second surface on the back side thereof;
a rotation drive unit that rotates the substrate holding unit;
a chemical liquid supply unit that supplies a chemical liquid to the substrate;
a heated fluid supply unit that supplies heated fluid to the substrate , the heated fluid nozzle discharging the heated fluid toward a second surface of the substrate held by the substrate holding unit; and an upstream end. a heated fluid line connected to a heated fluid supply source and a downstream end connected to the heated fluid nozzle; an upstream end connected to a cryogenic fluid source and a downstream end connected to the heated fluid line; a heated fluid supply unit having a low temperature fluid line that supplies a low temperature fluid at a temperature lower than the heated fluid to the heated fluid line;
a drain line that branches from the heated fluid line at a branch point downstream from a position where the low temperature fluid joins the heated fluid line;
a temperature sensor provided in the drain line;
a first on-off valve that opens and closes the drain line;
a second on-off valve provided in the heated fluid line downstream of the branch point;
a control unit;
Equipped with
The control unit includes:
a substrate temperature raising step of supplying the heated fluid to the substrate by the heating fluid supply unit to increase the temperature of the substrate;
After the substrate temperature raising step, while the rotation drive unit rotates the substrate at a first rotation speed, the heated fluid supply unit supplies the heated fluid to the second surface of the substrate, and The first surface of the substrate is supplied with the heated fluid as a prewetting liquid by the heated fluid supply section, or by supplying a chemical solution with the chemical solution supply section. a liquid film forming step of forming a liquid film of the prewetting liquid;
After the liquid film forming step, while the rotation drive unit rotates the substrate at a second rotation speed lower than the first rotation speed, the heated fluid supply unit supplies the heated fluid to the second rotation speed of the substrate. a chemical solution treatment step of treating the first surface of the substrate with the chemical solution by supplying the chemical solution to the first surface of the substrate by the chemical solution supply unit;
is configured to run
The control unit adjusts the temperature of the fluid discharged from the heated fluid nozzle by adjusting the mixing ratio of the low temperature fluid to the heated fluid,
The control unit opens the first on-off valve to drain the heated fluid from the drain line while keeping the second on-off valve closed until the temperature detected by the temperature sensor reaches a predetermined value. processing the substrate, closing the first on-off valve and opening the second on-off valve to discharge the heated fluid from the heated fluid nozzle when the temperature detected by the temperature sensor reaches a predetermined value. Device. The control unit is configured to control the temperature based on the temperature detected by the temperature sensor when the first on-off valve is opened and the heated fluid is flowing from the drain line with the second on-off valve closed. 15. The substrate processing apparatus according to claim 14 , wherein a mixing ratio of the cold fluid to the heated fluid is controlled.